Incomplete key depression key latch



April 2 1952 J. HMELEWSKY INCOMPLETE KEY DEPRESSION KEY LATCH MECHANISM Filed June 5. 1949 Patented Apr. 29, 1952 INCOMPLETE KEY DEPRESSION KEY LATCH MECHANISM Johannes Hmelewsky, Helsingfors, Finland Application June 3, 1949, Serial No. 97,038 In Sweden October 18, 1948 6 (Jlaims. 1

In calculating machines making use of a key board, faults in the calculating operations may be produced by the fact that a key is not depressed as far as to the bottom position, the result being then a failure in the tens transfer between two consecutive key depressions. Likewise, faults in the calculation may be caused by the fact that a key is depressed anew, before it has fully returned into its position of rest. The present invention has for its object to prevent such faults, and principally consists in that the keys are latch-controlled, in a manner such that the direction of movement of the key cannot be reversed, before the key has completed its movement. A latching device of this kind may be used for the control of the movement of depression of the key or of its return movement or, pref erably, of both of these movements. Thus, if a key should not happen to be depressed into the bottom position, it will be latched in its partly depressed position, whereby the attention of the operator of the machine i called to the fact that the key requires to be struck down into the bottom position to permit of being allowed to be returned into the position of rest. At the return movement, the latching device acts in a similar manner, so that the key cannot be actuated anew, before it has been permitted to return home into the position of rest.

The invention will be described more closely with reference to the accompanying drawing, which illustrates a latching device according to the invention and the parts of the calculating machine cooperating therewith. The drawing shows the invention as applied to a calculating machine of the kind described in the Swedish Patent 100,625, wherein adjustment of the accumulator is effected by means of 10 keys. ever, the invention is also applicable in other calculating machines.

The drawing shows at the right a key l with its appurtenant lever 2, which is swingably mounted on a fixed shaft 3. At the same time, thi shaft constitutes an oscillation shaft for a cradle 4, the so-called tabulating bridge, which carries the escapement mechanism, by means of which the tens transfer, that is to say the stepwise feeding of the computing wheel carriage, is controlled. The bridge consists of a plate provided with two bent-down lugs 5, by means of which it is mounted on the shaft 3. The escape mentmechanism consists of a toothed bar pro- Howpawls 9 and Ill, respectively. Said toothed bar 2 is secured at both ends to slide members 3! and 38 which together with the toothed bar form a slide which is slidable on fixed guide rods 39, passing through holes in the members 31, 33. The computing wheel carriage, which may be of any known construction and, therefore, is not shown in the drawing, is connected in known manner to the said slide so as to be carried along together with the toothed bar 6 in both directions of movement. The slide is actuated by a spring 4| through a lever 42 which engages a pin 43 on the bar 8. The pawl 9 is pivoted about a stud II and is retained bearing on a stop pin 13 by means of a spring 12. The pawl It is pivoted in a similar manner about a stud l4 secured on the bridge, and is kept bearing on a stop pin it by means of a spring l5. The portion of the bridge carrying the pawl 9 is bent so as to take a sloping position relatively to the remainder of the bridge. Arranged on the pawl H3 is a bar H, which is provided at the outer end thereof with a protrusion l8 cooperating with the teeth 8, and which is displaceable in its longitudinal direction while being guided by means of the stud l4 and a stud l9 provided in the pawl Hi. Said studs pass through longitudinally extending guide slits 20 and 21 respectively in the bar IT. The bar I1 is actuated by means of a spring 22 tending to keep the bar and the protrusion [8 in the retracted position shown in the drawing. Extending froni the one lug 5 on the bridge 4 in parallel to the keys is an arm 23 carrying a prism-like detent 24 and a bail 25 of a square cross section at the extreme end of the arm, said bail extending in the transverse direction over the levers. When the key is actuated, the key lever will thus raise the bail 25, the bridge 4 being swung at the same time about the shaft 3; For the sake of clarity, the drawing shows the key l and the key lever 2 as being arranged outside the bridge 3. Actually, however, all of the key levers are arranged underneath the bridge between the bearing points thereof, so that the bail 25 is raised at every depression of a key. One key l and its lever 2' is shown in such a position below the bridge. The key lever is adapted to be coupled to the bail 25 by means of a contrivance shown at the end of the key lever 2 and consisting of a snap hook M swingably mounted on the key lever so as to engage the bail when the latter is raised. The hook is actuated by a spring 415 and is arranged to cooperate with a curved guide 46 so as to be released from its locking position in the normal position of the key and the key lever. Immedi ately upon depressing the key the key .leveryis a a coupled with the bail 25 by the action of the guide 46 and the lever and the bail will then remain coupled together until they return into the position of rest.

The latching contrivance according to the invention consists of two locking members 26, 27 in the form of arms, which are swingable about a shaft 28 under the action of springs 29 and 36 respectively tending to move the locking members into engagement with the detent 24 and a detentlike milled-out portion 3| of the bail 25. Cooperating with said parts 24 and H are ratchet teeth 32 and 33 on the arms 26 and 2?, respectively, said ratchet teeth being arranged in such manner that the teeth 32 may lock the arm 23 at the upward movement thereof, that is to say at the depression of the key, while the teeth 33 may lock the arm 23 at the downward movement thereof, that is to say at the return movement of the key. The locking members are adapted to be alternately brought into the operative and the inoperative position respectively by a shifting member in the form of a bell crank lever M, which is pivoted about a vertical stud 35, one arm of the bell crank lever being kept bearing on the end of the bar H by means of a spring 36.

In the drawing, the key is shown as being depressed into the bottom position. Consequently, the bridge has been turned into its corresponding extreme position, wherein the toothed bar 6 is released by the pawl 9. The drawing shows the escapement mechanism at the moment of releasing the toothed bar t, when the latter by the action of the spring ti commences its movement in the direction indicated by the arrow. Before this takes place, however, the bail 25 has become raised into its uppermost position, the uppermost tooth of the locking member 27 being thus brought into its position of engagement underneath the detent 3 i. Hereby, the adjusting mech-- anism, which is positively connected to the bail, is locked for a moment in the exact position of adjustment, in a manner such that every return movement by a rebounding effect is prevented. The upward movement of the bail 25 has been permitted to take place without any hindrance by the locking member 25, which during this movement is kept in its operative position by the bell crank lever At the release of the toothed bar 6, the protrusion i8 is actuated by the corresponding tooth 8 of the toothed bar, the bar i! being then displaced so far as to bring the protrusion it into the same position as the pawl H], the tooth 8 being thus locked against the pawl Ill. Hereby, the carriage has been displaced by half a step toward the next position. Through the influence of the bar 11, the arm of the bell crank lever 34 cooperating with the locking members 26, 21 is turned into a position such that the locking member 26 is released, while the locking member 21 is moved out of its operative position to release the bail 25, so that the bridge 4 and the key lever A may return into the position of est under the influence of a spring 41 acting upon the bridge. When the bridge 4 returns into its initial position, the pawl S is brought into the position of engagement between the next pair of teeth I, while the pawl H3 and the protrusion 18 are moved out of the position of engagement relatively to the teeth 8 on the toothed bar 6. Consequently, the toothed bar and the wheel carriage are now displaced by a further half step into the new position of adjustment. When the bar I! is released, it is pulled back by thespring 22,.the ell crani lever 35 being thenreturned'into its 4 initial position through the influence of the spring 26, while the locking member 22' is returned into its position prepared for latching, and the locking member 2:6 is returned into its inoperative position.

Should the mechanism not be depr ssed down into the bottom position, it will be latched, together with the bridge 3- and the adjusting mechanism connected to the bail in an intermediate position the detent 31 coming into engagement with a ratchet tooth 33. Only after the key has been actuated anew and completed its downward movement will the mechanism be released, as just described, to be returned into its position of rest. Should the key be actuated anew during the return movement prior to having returned into its full position of rest, the mechanism is latched by the fact that the detend Ed is brought into engagement with a tooth 32 on the now operative locking member 26. The key must thus be permitted to return into its full position of rest, before it can be actuated anew.

What I claim is:

l. A calculating machine comprising a computing wheel carriage slide, numerical keys, an escapement mechanism for adjusting said slide into different digit positions, means actuated by the keys for operating said escapement mechanism, a ratchet device for locking any one of a plurality of the keys in any partially depressed position against retraction until the depression is completed, and similarly in any partially retracted position until the key is fully retracted, said ratchet device being arranged in common with respect to a plurality of the keys, and comprising a detent member and two ratchet members operative in opposite directions of movement of the detent member, means for connecting said detent member with each of said keys so as to cause the detent to follow the movement of the respective key in both directions, and a shifting member under the control of said escapement mechanism for rendering the ratchet device operative alternatively in one or the other direction of movement of the key.

2. A calculating mechanism according to claim 1, in which the ratchet device comprises means for locking the keys and the detent member against return movement until they have reached their extreme positions, and means for releasing the key and the detent member under the control of the shifting member.

3. A calculating machine according to claim 1,

in which the key actuated escapement mecha A nism is provided with means for moving the slide in two half-steps between consecutive key operations and in which means are provided for adjusting the shifting member into one extreme position at the commencement of the first half -step and into the other extreme position at the commencement of the second half-step.

i. A calculating machine according to claim 1, in which the ratchet members comprise swingable arms provided with ratchet teeth, the detent member being movable between said arms, and in which means is provided under the control of the shifting member for moving the ratchet members into operative and inoperative positions respectively, said means comprising a lever movable between said arms.

5. A calculating machine comprising a computing wheel carriage slide, numerical keys, an escapement mechanism for adjusting said slide in different digit positions, meai'isac'tuated by the keys for operating said escapement mechanism,

5 a ratchet device for locking the keys against return while they are in any partially depressed and partially retracted positions, said ratchet device being arranged in common with respect to a plurality of the keys, and comprising a detent member and two ratchet members operative in opposite directions of movement of, the detent member, means for connecting said detent member with any one of the keys so as to cause said member to follow the movement of the key in both directions, a shifting member under the control of said escapement mechanism for rendering the ratchet device operative and inoperative respectively in either direction of movement of the key, key operated levers swingable about a common axis, a member carryingsaid detent member and swingable about said axis, and a bar connected 6 with the detent member and extending transversely of said key operated levers in operative relation with said levers.

6. A calculating machine according to claim 5, in which the key operated levers are connected individually with the transversely extending bar.

JOHAN'NES HMELEWSKY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

